1. Field of the Invention
The present invention relates to a motor, and more particularly, to a motor having a rotor in which a plurality of core pieces and magnets are alternately arranged in the circumferential direction.
2. Description of the Related Art
FIGS. 1 to 3 are views illustrating an inner rotor motor among conventional motors.
As shown in FIGS. 1 to 3, the conventional motor is an inner rotor motor
The conventional motor shown in FIGS. 1 to 3 is an inner rotor motor in which a rotor 20 is rotatably installed in a stator 10 by a predetermined gap G and rotated due to the electromagnetic interaction between the rotor 20 and the stator 10.
The stator 10 includes a ring-shaped yoke 12, a plurality of teeth 14 radially arranged on the inner wall of the yoke 12, and coils 16 wound around the teeth 14 and electrically connected to an external electric power source.
The yoke 12 and the teeth 14 are formed by laminating a plurality of electric steel sheets.
The rotor 20 includes a cylindrical core 22 and a plurality of magnets 24 radially arranged in the core 22.
The core 22 may be formed with an axial hole 22′ penetrating the axial center of the core 22 in the axial direction. In the axial hole 22′ of the core 22, a rotation shaft (not shown) may be fitted to rotate together with the rotor 20.
The core 22 is also formed by laminating a plurality of electric steel sheets.
However, in the above mentioned conventional motor, as indicated by an arrow in FIG. 2, some of the magnetic flux of the magnets 24 leaks through the inner circumferential region between the magnets 24 and the axial hole 22′ of the core 22 in the radial direction of the core 22. Thus, due to the loss of magnetic flux, the performance of the conventional motor is limited.